The present disclosure generally relates to photovoltaic solar cells, and more particularly to thin film solar cells and methods for forming same.
Thin film photovoltaic (PV) solar cells are one class of energy source devices which harness a renewable source of energy in the form of light that is converted into useful electrical energy which can be used for numerous applications. Thin film solar cells are multi-layered semiconductor structures formed by depositing various thin layers and films of semiconductor and other materials on a substrate. These solar cells can be made into light-weight flexible sheets in some forms comprised of a plurality of individual electrically interconnected cells. The attributes of light weight and flexibility gives thin film solar cells broad potential applicability as an electric power source for use in portable electronics, aerospace, and residential and commercial buildings where they can be incorporated into various architectural features such as roof shingles, facades, and skylights.
Thin film solar cell semiconductor packages generally include a bottom contact or electrode formed on the substrate, an absorber, and a top contact or electrode formed above the bottom contact. Front contacts have been made for example of light transparent conductive oxide (“TCO”) materials. TCO materials are susceptible to attack and degradation by environment factors including water, oxygen, and carbon dioxide. Such TCO degradation may induce high series resistance (Rs) and result in lower solar energy conversions efficiencies for the solar cell.